Sedgemoor, Battle of(July 16 [July 6, Old Style], 1685), in English history, battle fought about 3 miles (5 km) southeast of Bridgwater, Somerset, Eng. It was a massacre of the mainly peasant supporters untrained smallholders and cloth-workers who had rallied to the support of James Scott, Duke of Monmouth, by troops of King James II led by Louis de Durfort, 2nd Earl of Feversham, and John Churchill (afterward Duke of Marlborough).

The Duke of Monmouth, illegitimate son of Charles II, had taken advantage of the popularity of his Protestantism to attempt to wrest the throne from his Roman Catholic uncle, James II. Landing at Lyme Regis in Dorset on June 11, he was proclaimed king at Taunton, failed to take Bristol, and fell back on Bridgwater. His path was then blocked by the royal army encamped on Sedgemoor. Monmouth decided on a hazardous night attack and very nearly succeeded; but his small force of cavalry fled, his foot soldiers failed to cross the ditch separating them from the royalist front, and, once the element of surprise was lost, Monmouth’s untrained and unofficered followers were cut down.

Monmouth was captured soon afterward and executed; many of his followers were condemned to death or transportation in the Bloody Assizes, a series of trials conducted by Lord Chief Justice George Jeffreys in the ensuing months.